Bobbin thread preplenishment mechanism for lockstitch sewing machines



M. F. IVANKO BOBBIN THREAD REPLENISHMENT MECHANISM FOR LOCKSTITCH SEWINGMACHINES June 4, 1968 3 Sheets- Sheet l Filed 00t- IS, 1967 INVENIORMichael F Ivanko WITNESS June 4, 1968 v M. F. IVANKO BOBBIN THREADREPLENISHMENT MECHANISM FOR LOCKSTITCH SEWING MACHINES 5 Sheets-Sheet 2Filed Oct. 16. 1967 INVENTOR- Mi hael E lvanko ATTORNEY June 4, 1968 M.F. IVANKO BOBBIN THREAD REPLENISHMENT MECHANISM FOR LOCKSTITCH SEWINGMACHINES 5 Sheets-Sheet 3 Filed Oct. 16. 1967 22 Michael E lvanko BYATTORNEY INVENTOR.

WITNESS fi/wqwgk United States Patent 3,386,400 BOBBIN THREADREPLENISHMENT MECHANISM FOR LOCKSTITCH SEWING MACHINES Michael F.Ivanko, Rockaway, N.J., assignor to The Singer Company, New York, N.Y.,a corporation of New Jersey Continuation-impart of application Ser. No.544,952, Apr. 25, 1966. This application Oct. 16, 1967, Ser. No. 675,498

8 Claims. (Cl. 112-181) ABSTRACT OF THE DISCLOSURE A. lockstitch sewingmachine is disclosed in which the rotation restraining means for thebobbin case in a circularly moving loop taker is associated withmechanism by which either one of two discrete angular positions of thebobbin case is attained. Needle thread manipulating means on the looptaker and on the bobbin case cooperate to influence the needle thread inone angular position of bobbin case to move about the bobbin case so asto form stitches, and in the other angular position of the bobbin caseto move onto the bobbin for replenishment of bobbin thread.

Cross reference to related application This application is acontinuation-in-part of United States application Ser. No. 544,952,filed Apr. 25, 1966, now abandoned.

Background of the invention This invention relates to lockstitch sewingmachines in which the bobbin thread may be replenished while the bobbinremains in the loop taker of the sewing machine, and more particularly,to a new and improved loop taker construction and means for operatingthe loop taker for drawing in, winding, and tensioning a fresh supply ofbobbin thread.

It is an object of this invention to provide novel and improved meansassociated with a loop taker of a lockstitch sewing machine forautomatically winding a fresh supply of thread on the bobbin in the looptaker.

Another object of this invention is to provide means effective in theloop taker of a sewing machine for selectively influencing bobbin threadreplenishment or sewing as the result of an angular shift of therestrained position of a bobbin case within the loop taker. With thenovel arrangement provided by this invention, bobbin threadreplenishment is effected without the necessity for the presence in theloop taker of any parts or instrumentalities which are not required forthe manipulation of threads during sewing. As a result, the novel meansof this invention may be applied readily to existing sewing machines orembodied conveniently in conventional sewing machine loop takers.

Description of the drawings With the above and additional objects andadvantages in view as will hereinafter appear, this invention comprisesthe devices, combination-s, and arrangements of parts hereinafterdescribed and illustrated in the accompanying drawings of a preferredembodiment in which:

FIG. 1 represents .a vertical cross sectional view of the sewing machineto which the loop taker and bobbin thread replenishing mechanism of thisinvention is applied,

FIG. 2 is an enlarged cross sectional view taken substantially alongline 22 of FIG. 1 and illustrating the loop taker and bobbin threadreplenishing mechanism,

FIG. 3 represents a bottom plan view of a fragment 3,385,403 PatentedJune 4, 1968 ICC of the bobbin thread replenishing mechanism of FIG. 2,

FIG. 4 is a vertical cross sectional view through the loop taker takensubstantially along line 4-4 of FIG. 2,

FIG. 5 is a perspective view of the loop taker including arepresentation of a needle thread loop seized by the loop taker beak andillustrating the position of the parts during normal sewing operationwith the bobbin thread being omitted.

FIG. 6 is a perspective view of the loop taker including arepresentation of a needle thread loop seized by the loop taker beak andillustrating the position of the parts during bobbin threadreplenishment,

FIG. 7 is a perspective view of the loop taker including arepresentation of the needle thread after bobbin thread replenishmenthas been effected, and

FIG. 8 represents a diagrammatic illustration of the relationship of aloop of needle thread seized by the loop taker beak relatively to thebobbin case.

Detailed description Referring to FIG. 1, the sewing machine to whichthis invention is applied includes a frame 11 in which is journaled amain shaft 12. A hollow loop taker drive shaft 13 is journaled in theframe parallel to the main shaft and is driven at twice the speed of themain shaft by means of a belt 14 and sprockets 15 and 16 on the mainshaft and loop taker drive shaft, respectively. A needle bar 17 carryinga needle 18 is supported for endwise reciprocation in the sewing machineframe and adapted to be operated in a conventional manner from the mainshaft 12. Secured to the machine frame beneath the needle 18 as byscrews 19 is a shuttle housing 20 formed with a raceway 21 in which ashuttle 22 is rotatable. Complemental to the shuttle raceway 21 is ashuttle retainer 23 which, as best illustrated in FIGS. 5 and 6, issustained against the shuttle housing by a pair of screws 24 and 25 eachthreaded into the shuttle housing and passing through arcuate slot-s 26and 27 in the shuttle retainer so that the shuttle retainer may partakeof limited angular adjustment relatively to the shuttle housing.

Referring to FIG. 4, the shuttle 22 is formed with a central post 30 onwhich is journaled a bobbin case 31 which is constrained on the post bymeans of a headed fastening screw 32 threaded into the central post 30of the shuttle. The bobbin case is formed with a substantiallycontinuous outer cover portion 33 from which a rotation restrainingfinger 34 projects radially. The rotation restraining finger 34 engagesbetween rotation restraining stop lugs 35 and 36 formed on the shuttleretainer 23. The bobbin case accommodates a thread carrying bobbin 37loosely journaled on a sleeve 38 of the bobbin case which embraces thecentral post 30 of the shuttle. The bobbin case cover portion 33envelops the bobbin and projects slightly into a shallow cavity 39 inthe shuttle 22. The bobbin case cover portion 33 is formed with a threadreceiving slot 40 which opens onto the bobbin within the bobbin case.

As shown in FIG. 6 of the drawings, the thread receiving slot 40 isinclined somewhat in the direction which the needle thread extends asthe thread is directed toward the slot. Moreover, the mouth of the slot40 at the outer periphery of the bobbin case cover portion 33 ispreferably flared as indicated at 44 to provide a sufliciently wideopening in the bobbin case cover portion 33 for the thread to enter. Itwill be understood that in place of the flared mouth 44, the entire slotcould be made sufficiently wide as to accept the thread for enhance tothe bobbin. A bobbin thread tensioning leaf spring 41 which is securedto the bobbin case by a screw 42 overlies a portion of the threadreceiving slot 40.

Referring to FIGS. 4 to 7, the shuttle 22 includes an annular bearingrib 50 which is constrained in the shuttle raceway 21 and which isformed with a peripheral gap 51 which accommodates the free extremity 52of a shuttle driver 53 fast on the loop taker drive shaft 13. Theshuttle bearing rib is formed with a needle thread loop seizing beak 54which projects into the gap 51 and which is formed with a throat 55 intowhich seized needle thread loops are carried.

The needle and loop taker arrangement described above are operated intimed relation by the shafts 12 and 13 interconnected by the belt 14 soas to impart two revolutions to the shuttle for each reciprocation ofthe needle so as to cooperate in a conventional fashion to producelockstitches comprising a needle thread and a thread carried by thebobbin 37. The sewing machine illustrated in FIG. 1 is of a cyclicallyoperated variety particularly suited for sewing predetermined groups ofstitches and includes a work holding clamp 60 and a pattern cam 61tracked by cam followers 62 and 63 operatively connected to impartmotion in mutually perpendicular directions to the work clamp as isconventional in group stitch sewing machines. The pattern cam 61 carriesa gear 64 meshing with a pinion 65 on a cam shaft 66 which is driven bymeans of a worm 67 and worm wheel 68 from the main shaft 12. The patterncam 61 is also utilized to effect manipulation of the loop taker in amanner such that thread may be replenished on the bobbin during selectintervals of the operation of the needle and loop taker. To this end acam follower shaft 70 is secured in a bushing bracket 71 fastened byscrews 72 to the machine frame and carries a rock arm '73 which tracksthe periphery of the pattern cam 61 so as to be operated by a cam lug 74attached to the pattern cam periphery. Clamped on the cam follower shaft70 are two spaced operating arms 75 and 76 which, as will be describedhereinbelow, serve to influence selectively either a thread replenishingor a sewing condition of the loop taker.

Referring to FIGS. 1 and 2, the operating arm 75 embraces one part 80 ofa pair of telescopically arranged rods 80, 81, which together areslidable endwise in the sewing machine frame 11. A coil spring 82 biasesthe telescoping rods 80 and 81 apart. By means of a connection block 83the telescoping rods 80 and 81 engage a rod 84 which is carriedcoaxially within the hollow loop taker shaft 13. Between the shuttle andthe shuttle driver 53 a thread clamping member '85 is secured to the rod84. The thread clamping member is locked for rotation with the looptaker drive shaft by a transverse pin 86 accommodated in a lengthwiseelongate slog 87 in the loop taker drive shaft but passing snuglythrough the rod 84. The pin 86 is secured in a collar 88 slidable on theloop taker drive shaft 13 and biased in a direction away from theshuttle by a coil spring 89 which acts between the collar 88 and acollar 90 secured as by a set screw 91 to the loop taker drive shaft 13.The thread clamping member 85 is formed with a radial extendingprojection 92 disposed adjacent to the throat 55 behind the threadengaging beak 54 of the shuttle in such a position that when the threadclamping member 85 is shifted into engagement with the shuttle by meansof the cam 74 a needle thread loop seized by the shuttle beak will beclamped securely in the throat 55 by the projection 92.

The second operating arm 76 on the cam follower shaft 70 is looselysecured by a headed screw 99 to One extremity of a push rod 100 whichpasses loosely through an aperture 101 formed in one arm 102 of a bellcrank lever 103 fulcrum at 104 beneath the sewing machine frame. Theother arm 105 of the bell crank lever 103 extends into a clearanceaperture 106 formed in a projection 107 of the shuttle retainer 23. Acompression spring 108 is carried on the rod 100' between the bell crankarm 102 and a collar 109 secured to the rod 100 so that the movement ofthe rod 100 can exceed that to which the bell crank lever 103 is moved,with the compression spring 108 absorbing the difference. A collar 110secured on the rod 100 at the opposite side of the bell crank lever 102from the compression spring 108 serves to return the bell crank leverwhen the push rod 100 is retracted. The retraction is effected by theaction of the springs 82 and 89 and by way of the operating arms and 76.

With reference to FIGS. 5 and 6, it will be appreciated that by means ofthe bell crank lever 103 and its action upon the shuttle retainer 23 theangular position of restraint of the bobbin case may be selectivelychanged. FIG. 5 illustrates the sewing position of the parts in whichthe bobbin case has been turned in a counterclockwise direction and FIG.6 illustrates the position of the parts bobbin thread replenishing willtake place in which the bobbin case has been turned in a clockwisedirection. The manner in which such angular shift of the bobbin case caninfluence thread replenishment or sewing might best be understood withreference to FIG. 8 which illustrates diagrammatically a number ofdifferent angular positions of the loop seizing beak 54 of the shuttlefrom a position indicated at A in which the beak 54 begins needle threadloop seizure and in a sequence A I, is the seized needle thread loop iscarried onto the bobbin case cover portion 33. As illustrated in FIG. 8,the seized needle thread loop will first assume a position of tangencyto the bobbin case cover portion 33 when the loop seizing beak occupiesa position as illustrated in FIG. 8 and indicated at I with the point oftangency being indicated by the arrow xx. If the mouth 44 of the threadentrance slot 40 in the bobbin case is disposed in a counterclockwisedirection from the station xx, the thread will bypass the threadentrance slot and be carried about the bobbin case so that sewing willtake place. FIG. 5 illustrates this arrangement of parts and the threadwhich occupies a position of tangency with the periphery of the bobbincase cover portion. FIG. 5 thus illustrates the means in which theseized needle thread loops will bypass the thread entrance slot 40 inthe bobbin case during sewing.

When the bobbin case is shifted angularly into a position in which themouth 44 of the thread entrance slot 40 is disposed in a clockwiseposition beyond the position xx as illustrated in FIG. 8 the seizedthread when it is carried by the loop seizing beak into tangency withthe bobbin case cover portion 33 will draw the thread into the threadentrance slot 40 and thus onto the bobbin. FIG. 6 illustrates thisposition of parts and indicates the manner in which the thread Will bedrawn into the slot 40 when the bobbin case is turned clockwise toposition the mouth of the thread entrance slot 40 clockwise beyond theposition xx indicated in FIG. 8.

Since the angular shift of the bobbin case 31 by the cam 74 is effectedsimultaneously with the movement of the thread clamping member intothread clamping position against the rear of the shuttle, the needlethread loop which is directed into the thread entrance slot 40 of thebobbin case will remain clamped to the shuttle beak throughout thebobbin thread replenishing operation. Further rotation of the main shaft12 and loop taker shaft 13 will effect winding of coils of the needlethread onto the bobbin until the cam 74 terminates the bobbin threadreplenishing operation by acting upon the cam follower shaft 70 toreturn the rods 84 and 100. The bobbin case 31 will then be shiftedcounterclockwise as viewed in FIG. 5 into the sewing position and onsubsequent penetrations of the needle, lock stitches will be formedutilizing the needle thread and the thread which had been wound upon thebobbin.

Although this invention is illustrated in the drawings as embodied in acyclic sewing machine in which the controls for alternativelyreplenishing bobbin thread or sewing emanate from a cam 74, it will beappreciated that any other means for influencing the angular position ofthe bobbin case so as to effect selectively sewing and admittance ofthread into the bobbin case for bobbin re- 5 plenishment would comewithin the preview of this invention.

It is also pointed out that this invention is not limited to usage witha shuttle, but will find utility with any circularly moving loop takersuch as a rotary hook in which the loop seizing beak manipulates needlethread loops relatively to a bobbin case which is restrained fromcircular movement with the loop taker.

Having thus set forth the nature of this invention, what is claimedherein is:

1. Lockstitch forming instrumentalities for a sewing machine including aloop taker comprising a bearing portion formed with a loop seizing beak,means supporting said loop taker bearing portion for circular movementin said sewing machine, a bobbin case journaled relatively to said looptaker bearing portion, a thread carrying bobbin journaled in said bobbincase, and means for restraining said bobbin case from circular movementwith said loop taker bearing portion, means for replenishing thread onsaid bobbin in place in said bobbin case including means for rotatablyshifting the angular position in which said bobbin case is maintained bysaid restraining means, and means rendered effective by said shifting ofsaid bobbin case into a predetermined angular position for replenishingthread on said bobbin in place in said loop taker.

2. A lockstitch sewig machine comprising a frame, a thread carryingneedle endwise reciprocable in said frame, a loop taker journaled forcircular movement in said frame, a needle thread engaging beak on saidloop taker, actuating mechanism operating said needle and loop taker incooperative timed relation required for the formation of lockstitches, abobbin case journaled relatively to said loop taker, a thread carryingbobbin journaled in said bobbin case, means for restraining said bobbincase from circular movement with said loop taker, means for shiftingsaid restraining means to vary the stationary angular position of saidbobbin case, thread manipulating means on said loop taker and on saidbobbin case effective in one stationary angular position of said bobbincase for manipulating needle thread loops engaged by said beakcompletely about said bobbin case in the formation of lockstitches, andeffective in another stationary angular position of said bobbin case formanipulating at least one limb of a needle thread loop engaged by saidbeak onto said bobbin in said bobbin case for replenishing thread onsaid bobbin.

3. A lockstitch sewing machine as set forth in claim 2 in which saidthread manipulating means includes means formed on said bobbin casedefining a passageway for the introduction of thread from said loopseizing beak onto said bobbin, and in which said means for shifting saidbobbin case restraining means positions said thread introductionpassageway alternatively into or out of coincidence with at least oneposition of a needle thread loop being manipulated by said loop-seizingbeak.

lower means responsive to said cam means and operatively connected tocontrol said means for alternatively shifting said bobbin caserestraining means.

5. A lockstitch sewing machine as set forth in claim 2 which includes athread clamping member cooperating with said hook beak to secure aseized loop of needle thread thereon, cam means driven by said actuatingmechanism for said needle and loop taker, first cam follower meansresponsive to said cam means and operatively connected to control saidthread clamping member, and second cam follower means responsive to saidcam means and operatively connected to control said means foralternatively shifting said bobbin case restraining means.

' 6. A shuttle mechanism for a lockstitch sewing machine comprising ashuttle housing fixed in said sewing machine, a shuttle retainercontiguous to said shuttle housing, said shuttle housing and shuttleretainer formed with cooperating annular surfaces defining a shuttlerace, a shuttle journaled for circular movement in said shuttle race andformed with a loop seizing beak, a bobbin case journaled relatively tosaid shuttle and a bobbin freely journaled in said bobbin case, meansconstraining said shuttle retainer for limited angular movement relativeto said shuttle housing coaxially of said shuttle race, a rotationrestraining finger formed on said bobbin case, rotation restraining lugsformed on said shuttle retainer straddling said rotation restrainingfinger so as to move said finger with said shuttle retainer, a mechanismfor replenishing thread on said bobbin carried on said sewing machineand operatively connected to said shuttle retainer for varying thenagular position of said shuttle retainer relatively to said shuttlehousing one angular position of said shuttle retainer being for sewingand another angular position being for replenishing said bobbin.

7 A shuttle mechanism as set forth in claim 6 in which said bobbin caseis formed with a substantially radial thread accommodating grooveopening onto said bobbin, said thread accommodating groove being locatedon said bobbin case so as to be positionable into coincidence with thepath of a thread seized and being manipulated by said shuttle beak inresponse to operation of said means for varying the angular position ofsaid shuttle retainer relatively to said shuttle housing.

8. A shuttle mechanism as set forth in claim 7 which includes a bobbinthread tensioning spring carried by said bobbin case and overlying saidthread accommodating slot.

References Cited UNITED STATES PATENTS 1,077,056 10/1913 Dorsey 112-1862,016,364 10/1935 Dixon.

2,822,773 2/1958 Ivanko.

3,012,530 12/1961 Ketterer et a1. 112-481 3,063,392 11/1962 Ketterer etal. 112-181 3,096,736 7/1963 Johnson 112181 3,145,673 8/1964 Meloy112--181 3,308,776 3/1967 Ivanko et a1. 1l2-181 HERBERT F. ROSS, PrimaryExaminer.

